Apparatus of the aforementioned type are sufficiently known in the art. The piles of bulk material can be pure storage piles or mixed piles in which different bulk materials can be loosely stored (piled up), such as for example cement raw materials, ores or the like.
In these known constructions a scraper arrangement which is arranged like a jib so as to be movable along a bridge (back-loading bridge) which is movable relative to an inclined face (front face) of the pile of bulk material, and this scraper arrangement can be brought into scraping engagement with this inclined face in such a way that the bulk material stored there is loosened and can trickle down to a conveyor arrangement which is also supported by the bridge in the region of the toe of the pile; this conveyor arrangement then delivers the cleared loose bulk material, generally in the cross direction, to a further conveyor arrangement. Scraper arrangements of a known type which are more or less wide--in comparison with the width of the inclined face to be cleared--can be used, for example beam-like scraper arrangements, rope-operated rakes, scraper rakes or the like. Continuously circulated scraper chains which are equipped with individual scraper blades and are guided on rollers through guide rails can preferably be used as the scraper arrangement on the underside of the bridge.
In these known clearing devices, so long as the bulk material stored in the pile consists of only relatively fine or medium-sized lumps, i.e., does not contain larger stones, the bulk material cleared from the bulk material pile on the said inclined face can be removed largely without problems by the conveyor arrangement of the bridge. However, if the bulk material stored in the pile contains large stones or stone chippings then the bulk material can no longer be readily back-loaded or removed with the said conveyor arrangement. It should be noted here that the majority of these large stones and stone chippings are located at the toe of the heap and the scraper blades of the conveyor arrangement which is constructed in particular as a scraper chain would work against these heavy stones which lie at the toe of the heap and thus at the bottom of the heap, and this leads to severe damage to the scraper blades, the rollers, the guide rails and also the scraper chain, since above all the thick stones in the region of the toe of the heap push the scraper blades upwards.
The object of this invention is to provide an improved apparatus of the general type described above wherein it is ensured with relatively simple means that large stones and stone chippings present in the bulk material in the region of the toe of the heap can also be taken up and removed without problems by the conveyor arrangement arranged on the bridge.